Driving assistance device, vehicle, and driving assistance method

ABSTRACT

A driving assistance device is provided. An acquisition unit configured to acquire data regarding a travel trajectory of another vehicle from the other vehicle by vehicle-to-vehicle communication. A specifying unit configured to specify an intersection position between the travel trajectory of the other vehicle and a travel trajectory of a self-vehicle based on the data acquired by the acquisition unit. A selection unit configured to select data for setting a region based on the intersection position and the travel trajectory of the other vehicle as a monitoring region when performing driving assistance in a case where the intersection position is specifiable by the specifying unit. The selection unit selects data that has been partially deleted from the data acquired by the acquisition unit based on the intersection position.

CROSS-REFERENCE TO RELATED APPLICATION(S)

This application claims priority to and the benefit of Japanese PatentApplication No. 2021-038559, filed Mar. 10, 2021, the entire disclosureof which is incorporated herein by reference.

BACKGROUND OF THE INVENTION Field of the Invention

The present invention relates to a driving assistance device, a vehicle,and a driving assistance method.

Description of the Related Art

A device that prevents a collision with another vehicle or the like atan intersection or the like has been known. Japanese Patent Laid-OpenNo. 2013-33505 discloses an on-vehicle device that determines a risk ofa collision with another vehicle or the like using map information.

SUMMARY OF THE INVENTION

According to one embodiment of the present invention, there is provideda driving assistance device comprising: an acquisition unit acquiresdata regarding a travel trajectory of another vehicle from the othervehicle by vehicle-to-vehicle communication; a specifying unit specifiesan intersection position between the travel trajectory of the othervehicle and a travel trajectory of a self-vehicle based on the dataacquired by the acquisition unit; and a selection unit selects data forsetting a region based on the intersection position and the traveltrajectory of the other vehicle as a monitoring region when performingdriving assistance in a case where the intersection position isspecifiable by the specifying unit, wherein the selection unit selectsdata that has been partially deleted from the data acquired by theacquisition unit based on the intersection position.

According to another embodiment of the present invention, there isprovided a vehicle on which the driving assistance device of the aboveembodiment is mounted.

According to still another embodiment of the present invention, there isprovided a driving assistance method comprising: acquiring dataregarding a travel trajectory of another vehicle from the other vehicleby vehicle-to-vehicle communication; specifying an intersection positionbetween the travel trajectory of the other vehicle and a traveltrajectory of a self-vehicle based on the data acquired in theacquiring; and selecting setting data for setting a region based on theintersection position and the travel trajectory of the other vehicle asa monitoring region when performing driving assistance in a case wherethe intersection position is specifiable in the specifying, wherein, inthe selecting, data that has been partially deleted from the dataacquired in the acquiring based on the intersection position isselected.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagram illustrating a configuration example of a vehicleaccording to an embodiment;

FIG. 2A is a diagram illustrating a configuration example of anintersection position database (DB);

FIG. 2B is a diagram illustrating a configuration example of amonitoring region DB;

FIG. 3A is a diagram for describing setting of a monitoring region;

FIG. 3B is a diagram for describing the setting of the monitoringregion;

FIG. 4A is a flowchart illustrating a processing example of a processingunit;

FIG. 4B is a diagram illustrating an example of a situation in whichdriving assistance of the vehicle is performed;

FIG. 5 is a flowchart illustrating a processing example of theprocessing unit;

FIG. 6 is a diagram illustrating a situation when the processing of FIG.5 is performed;

FIG. 7A is a diagram illustrating data acquired from another vehicle;

FIG. 7B is a diagram illustrating an angular difference between eachposition of another vehicle and a previous position;

FIG. 8 is a flowchart illustrating a processing example of theprocessing unit;

FIG. 9 is a flowchart illustrating a processing example of theprocessing unit;

FIG. 10 is a flowchart illustrating a processing example of theprocessing unit;

FIG. 11 is a flowchart illustrating a processing example of theprocessing unit; and

FIG. 12 is a flowchart illustrating a processing example of theprocessing unit.

DESCRIPTION OF THE EMBODIMENTS

Meanwhile, there is a device that performs driving assistance forpreventing a collision with another vehicle or the like without usingmap information. In such a device, for example, a monitoring region foranother vehicle is set based on data acquired from the other vehicle byvehicle-to-vehicle communication, and driving assistance may beperformed when the other vehicle travels in the set monitoring region.It is desirable that the data used for setting the monitoring region isappropriately selected from the viewpoint of reducing the amount of datastored in the device.

An embodiment of the present invention provides a technique for reducingthe amount of data used for setting a monitoring region for anothervehicle in driving assistance.

Hereinafter, embodiments will be described in detail with reference tothe attached drawings. Note, the following embodiments are not intendedto limit the scope of the claimed invention, and limitation is not madeto an invention that requires a combination of all features described inthe embodiments. Two or more of the multiple features described in theembodiments may be combined as appropriate. Furthermore, the samereference numerals are given to the same or similar configurations, andredundant description thereof is omitted.

1. Overall Configuration (FIGS. 1 to 2B)

FIG. 1 is a diagram illustrating a configuration example of a vehicle 1according to an embodiment. Note that FIG. 1 illustrates a configurationrelated to features of embodiments to be described later. The vehicle 1is a vehicle capable of performing driving assistance for preventing acollision with another vehicle or the like without using map informationby a control to be described later. The vehicle 1 includes a controldevice 10, a sensor group 11, a global positioning system (GPS) antenna12, a vehicle-to-vehicle communication antenna 13, a notification device14, and a braking device 15.

The control device 10 is, for example, an electronic control unit (ECU),and functions as a driving assistance device that performs a drivingassistance control. Although details will be described later, in thepresent embodiment, the control device 10 performs a driving assistancecontrol by vehicle-to-vehicle communication with another vehicle andprocessing in the self-vehicle without performing server communicationor the like. The control device 10 includes a processing unit 101, astorage unit 102, and a communication unit 103, which are connected by abus (not illustrated).

The processing unit 101 is a processor as typified by a centralprocessing unit (CPU), and executes a program stored in the storage unit102. The storage unit 102 is a random access memory (RAM), a read onlymemory (ROM), a hard disk drive, or the like and stores various data inaddition to the program executed by the processing unit 101. Thecommunication unit 103 is a communication interface for communicationwith an external device.

In the present embodiment, an intersection position database (DB) 1021and a monitoring region DB 1022 are constructed as databases forperforming driving assistance in the storage unit 102.

FIG. 2A is a diagram illustrating a configuration example of theintersection position DB 1021. The intersection position DB 1021 storesinformation regarding an intersection position registered by processingto be described later. In the present embodiment, the intersectionposition DB 1021 stores an intersection position ID, a registration dateand time, position information, and an entry azimuth in association witheach other for each intersection position.

The intersection position ID is an identification number of eachintersection position. The registration date and time is a date and timewhen a target intersection position is registered in the intersectionposition DB 1021. The position information is information indicating theintersection position, and is indicated by, for example, latitude andlongitude. Furthermore, the position information may include informationregarding a height such as altitude. The entry azimuth is an azimuth(angle) at which the vehicle 1 is directed at the time of entering theintersection position when the intersection position is registered. Inthe present embodiment, the azimuth of entry to the intersection isregistered with the north direction set to 0°, the east direction set to90°, the south direction set to 180°, and the west direction set to270°.

Note that the information stored in the intersection position DB 1021 asillustrated in FIG. 2A is an example, and the information included inthe intersection position DB 1021 can be changed as appropriate. In thefollowing description, the intersection position registered in theintersection position DB 1021 may be referred to as a registeredintersection position.

FIG. 2B is a diagram illustrating a configuration example of themonitoring region DB 1022. The monitoring region DB 1022 storesinformation regarding a monitoring region set by processing to bedescribed later. Here, the monitoring region is a region to be monitoredfor another vehicle when the control device 10 performs drivingassistance. That is, the control device 10 performs driving assistancewhen another vehicle is traveling in the monitoring region. In thepresent embodiment, the monitoring region DB 1022 stores a monitoringregion ID, an intersection position ID, and monitoring region settinginformation in association with each other for each monitoring region.

The monitoring region ID is an identification number of each monitoringregion. In the present embodiment, since the monitoring region is setfor the registered intersection position, the monitoring region DB 1022also includes the intersection position ID of the intersection positioncorresponding to the monitoring region specified by the monitoringregion ID. Monitoring region information is information for setting themonitoring region. For example, the monitoring region informationincludes time series data of a position of another vehicle used forsetting the monitoring region.

The communication unit 103 includes a GPS module 1031 that receivesposition information and the like of the vehicle 1 from an artificialsatellite (GPS satellite) via the GPS antenna 12, and avehicle-to-vehicle communication module 1032 that receives informationfrom another vehicle via the vehicle-to-vehicle communication antenna13.

Note that the function of the control device 10 can be implemented byeither hardware or software. For example, the function of the controldevice 10 may be implemented by a central processing unit (CPU)executing a predetermined program using a memory. For example, at leastsome of the functions of the control device 10 may be implemented by aknown semiconductor device such as a programmable logic device (PLD) oran application specific integrated circuit (ASIC). In addition, here,the control device 10 is described as a single element, but the controldevice 10 may be divided into two or more elements as necessary.

The sensor group 11 includes various sensors mounted on the vehicle 1and necessary for driving assistance. For example, the sensor group 11can include an acceleration sensor that detects the acceleration of thevehicle 1, a vehicle speed sensor that detects the speed of the vehicle1, and the like. Furthermore, for example, the sensor group 11 caninclude an outside detection sensor such as a camera capable ofdetecting an object around the vehicle 1, a millimeter wave radar, or alight detection and ranging (LIDAR). The sensor group 11 outputs adetection result to the control device 10.

The GPS antenna 12 receives radio waves for position measurementtransmitted from a GPS satellite. The vehicle-to-vehicle communicationantenna 13 is an antenna that transmits and receives various data to andfrom another vehicle. For example, the vehicle-to-vehicle communicationantenna 13 may receive data regarding a travel trajectory of anothervehicle from the other vehicle.

The notification device 14 is a device that makes a notification for anoccupant. For example, the notification device 14 includes a displayunit such as a display, and makes a notification for the occupant bydisplaying information such as a possibility of a collision with anothervehicle on the display unit. Furthermore, for example, the notificationdevice 14 includes a voice output unit such as a speaker, and notifiesof information such as a possibility of a collision by voice.

The braking device 15 is, for example, a brake, and is a device forperforming a braking operation of the vehicle 1. When there is apossibility that the vehicle 1 collides with another vehicle, as drivingassistance, the control device 10 may operate the braking device 15 toavoid the collision with another vehicle.

2. Outline of Operation of Control Device 10 (FIGS. 3A to 4B)

In the present embodiment, the control device 10 of the vehicle 1performs driving assistance without using the map information. Here, theoperation performed by the control device 10 is mainly divided intosetting of the monitoring region and execution of driving assistance.Specifically, the control device 10 specifies the intersection positionwhere a travel trajectory of the vehicle 1, which is the self-vehicle,and the travel trajectory of another vehicle intersect, and sets themonitoring region based on the specified intersection position. Then,when the vehicle 1 approaches the specified intersection position, thecontrol device 10 performs driving assistance with another vehicletraveling in the monitoring region as a monitoring target. The outlineof the setting of the monitoring region and the driving assistance willbe described below.

2.1. Setting of Monitoring Region

FIGS. 3A and 3B are diagrams for describing the setting of themonitoring region. Here, a case where the travel trajectory of thevehicle 1 that is the self-vehicle and the travel trajectory of avehicle 9 that is another vehicle intersect will be described.

FIG. 3A illustrates a state before the travel trajectories of thevehicle 1 and the vehicle 9 intersect. Specifically, FIG. 3A illustratesa state in which the vehicle 9 is about to cross the front of thevehicle 1 in a state in which the vehicle 1 is stopped before a stopline.

FIG. 3B illustrates a state after the travel trajectories of the vehicle1 and the vehicle 9 intersect. Details will be described later, and thecontrol device 10 specifies an intersection position 5 between thetravel trajectory of the vehicle 9 and the travel trajectory of thevehicle 1. For example, the control device 10 calculates a traveltrajectory 98 of the vehicle 9 based on information regarding aplurality of positions 97 acquired from the vehicle 9. In addition, thecontrol device 10 calculates a travel trajectory 18 of the vehicle 1based on information regarding a plurality of positions 17 of thevehicle 1 acquired via the GPS antenna 12. Then, an intersection betweenthe travel trajectory 98 and the travel trajectory 18 is specified asthe intersection position 5. In addition, the control device 10 storesinformation regarding the specified intersection position 5 in theintersection position DB 1021.

In addition, FIG. 3B illustrates a monitoring region 99 set based on thetravel trajectory and the intersection position 5 of the vehicle 9. Aswill be described in detail later, the control device 10 sets, as themonitoring region 99, a region having a predetermined width around thetravel trajectory 98 in a portion in front of the intersection position5 of the travel trajectory 98. The predetermined width may be set to,for example, several meters in consideration of a general lane width. Inaddition, the control device 10 stores information regarding the setmonitoring region 99 in the monitoring region DB 1022.

2.2. Driving Assistance

FIG. 4A is a flowchart illustrating a processing example of theprocessing unit 101. FIG. 4A illustrates a processing example of theprocessing unit 101 when performing driving assistance. For example,this flowchart is implemented by the processing unit 101 reading andexecuting a program stored in the storage unit 102. Further, forexample, this flowchart is repeatedly executed while the vehicle 1 istraveling.

FIG. 4B is a diagram illustrating an example of a situation in whichdriving assistance of the vehicle 1 is performed. Here, a situation inwhich the vehicle 1 enters the intersection registered in theintersection position DB 1021 is illustrated.

In Step S91 (hereinafter, simply referred to as S91, and the sameapplies to other steps), the processing unit 101 searches for aregistered intersection position around the vehicle 1. For example, theprocessing unit 101 searches for a registered intersection positionwithin a predetermined range from the vehicle 1 based on the currentposition of the vehicle 1 acquired by the GPS module 1031 and positioninformation regarding the intersection position registered in theintersection position DB 1021. In the situation illustrated in FIG. 4B,the processing unit 101 searches for an intersection position that isregistered in the intersection position DB 1021 and that is within asearch range R in front of or on the side of the vehicle 1.

In S92, the processing unit 101 proceeds to S93 in a case where there isa registered intersection position around the vehicle 1 based on thesearch result of S91, and ends the flowchart in a case where there is noregistered intersection position around the vehicle 1. In the situationillustrated in FIG. 4B, since the intersection position 5 is included inthe search range R, the processing unit 101 proceeds to S93.

In S93, the processing unit 101 checks whether or not there is anothervehicle in the monitoring region, and in a case where there is anothervehicle, the processing unit 101 proceeds to S94, and in a case wherethere is no other vehicle, the processing unit ends the flowchart. Forexample, the processing unit 101 checks whether or not there is anothervehicle in the monitoring region based on position information ofanother vehicle acquired by the vehicle-to-vehicle communication module1032 through vehicle-to-vehicle communication. For example, theprocessing unit 101 checks whether or not there is another vehicle inthe monitoring region based on a detection result of the outsidedetection sensor capable of detecting an object around the vehicle 1. Inthe situation illustrated in FIG. 4B, since the vehicle 9 is travelingin the monitoring region 99, the processing unit 101 proceeds to S94.

In S94, the processing unit 101 performs driving assistance. Forexample, the processing unit 101 determines a possibility of a collisionbetween the vehicle 1 and the vehicle 9 based on information such as theposition and speed of the vehicle 1, which is the self-vehicle, and theposition and speed of the vehicle 9, which is another vehicle. Then, ina case where the possibility of the collision exceeds a threshold, theprocessing unit 101 causes the notification device 14 to notify theoccupant that there is a possibility of a collision. Alternatively, in acase where the possibility of the collision exceeds the threshold, theprocessing unit 101 may cause the braking device 15 to perform anemergency stop or the like of the vehicle 1. Note that a known techniquecan be appropriately adopted as an aspect of driving assistance.

As described above, in the present embodiment, the control device 10 isconfigured to be able to perform driving assistance in a case whereanother vehicle is present in the monitoring region. Therefore, thecontrol device 10 can perform driving assistance based on the setmonitoring region. In addition, since the control device 10 makes, asdriving assistance, a notification for the occupant of the self-vehicle,it is possible to urge the occupant to grasp the surrounding situationof the self-vehicle.

3. Control Example (FIGS. 5 to 8)

As described above, the control device 10 performs driving assistancebased on the set intersection position 5 and monitoring region 99. It isdesirable that data used for setting the monitoring region 99 isappropriately selected from the viewpoint of reducing the amount of datastored in the storage unit 102. Therefore, in the present embodiment,the amount of data used for setting the monitoring region 99 is reducedby deleting a part of the data acquired from another vehicle by theprocessing as described below.

3.1. Intersection Position Registration Processing

FIG. 5 is a flowchart illustrating a processing example of theprocessing unit 101, and illustrates a processing example ofintersection position registration processing. FIG. 6 is a diagramillustrating a situation when the processing of FIG. 5 is performed. Forexample, the flowchart of FIG. 5 is implemented by the processing unit101 reading and executing a program stored in the storage unit 102. Inaddition, for example, this flowchart is repeatedly performed while thevehicle 1 is traveling, and can be performed in parallel with theprocessing when performing driving assistance illustrated in FIG. 4A.

In S10, the processing unit 101 acquires data of another vehicle.Furthermore, the processing unit 101 acquires data regarding the traveltrajectory of the vehicle 9 from the vehicle 9 which is the othervehicle by vehicle-to-vehicle communication. For example, the vehicle 9,which is the other vehicle, transmits data regarding the traveltrajectory to the surrounding vehicle and the like on a predeterminedcycle by vehicle-to-vehicle communication. The processing unit 101receives data regarding the travel trajectory periodically transmittedfrom the surrounding vehicle 9. FIG. 7A is a diagram illustrating dataacquired from another vehicle. In FIG. 7A, data regarding positions 970to 977 of the vehicle 9 and orientations 960 to 967 of the vehicle 9 attimes t0 to t7 is included (see FIG. 6). That is, the data acquired bythe processing unit 101 in S10 may include data indicating the positionand orientation of another vehicle in time series. Further, in FIG. 7A,data regarding vehicle speeds v0 to v7 of the vehicle 9 and whether ornot a turn signal is lighted at the times t0 to t7 is included. That is,the data acquired by the processing unit 101 in S10 may include dataregarding whether or not the turn signal of another vehicle is lighted.In addition, the times t0 to t7 do not have to correspond to a constanttime interval. For example, when traveling on a curve, the vehicle 9 mayacquire and store data regarding the position and orientation at a timeinterval shorter than that at the time of traveling straight, by usingsteering angle information or the like. As a result, it is possible toaccumulate more accurate data regarding the travel trajectory at thetime of traveling on a curve or the like. The processing unit 101temporarily stores the acquired data in the storage unit 102. Note thatthe processing unit 101 ends the flowchart in a case where data cannotbe acquired from another vehicle due to the absence of another vehiclein the vicinity or the like.

Note that the number of data indicating a position included in data D1can be appropriately set. In addition, the number of data indicating theposition included in the data D1 may vary. For example, in a case wherea time at which the data D1 is transmitted by the vehicle 9 is set as areference time, data indicating a position acquired within apredetermined period up to the reference time may be included in thedata D1. As another aspect in which the number of data indicating theposition included in the data D1 varies, in a case where a positionwhere the data D1 is transmitted by the vehicle 9 is set as a referenceposition, the data D1 may include data indicating a position acquired ata position within a predetermined distance from a reference position.

In S11, the processing unit 101 recognizes travel trajectories of thevehicle 1 and the vehicle 9. For example, the processing unit 101calculates a travel trajectory 981 of the vehicle 9 based on the dataacquired in S10. More specifically, the processing unit 101 recognizesthe travel trajectory 981 by drawing a straight line connecting thepositions 970 to 977 of the vehicle 9 acquired in S11 in time series. Inaddition, the processing unit 101 calculates a travel trajectory 181 ofthe self-vehicle based on the data acquired from the GPS module 1031 orthe sensor group 11. For example, the processing unit 101 may acquirethe data from the GPS module 1031 or the sensor group 11 on apredetermined cycle to recognize the position of the vehicle 1 in timeseries and calculate the travel trajectory 181 of the vehicle 1. Morespecifically, the processing unit 101 recognizes the travel trajectory181 by drawing a straight line connecting acquired positions 170 to 172of the vehicle 1 in time series.

In S12, the processing unit 101 specifies an intersection position. Theprocessing unit 101 specifies the intersection position of the vehicle 1and the vehicle 9 based on the travel trajectories of the vehicle 1 andthe vehicle 9 recognized in S11. That is, the processing unit 101specifies the intersection position between the travel trajectory ofanother vehicle and the travel trajectory of the self-vehicle based onthe data acquired in S11. Specifically, the processing unit 101 mayspecify the intersection position by obtaining coordinates (latitude andlongitude) of an intersection between the straight line connecting thepositions 970 to 977 of the vehicle 9 acquired in S11 in time series andthe straight line connecting the positions 170 to 172 of the vehicle 1in time series.

In S13, the processing unit 101 proceeds to S14 in a case where theintersection position can be specified in S12, and the processing unit101 proceeds to S17 in a case where the intersection position cannot bespecified.

In S14, the processing unit 101 stores information regarding thespecified intersection position in the intersection position DB 1021 ofthe storage unit 102.

In S15, the processing unit 101 performs data selection processing. Morespecifically, in a case where the intersection position can be specifiedin S12, the processing unit 101 selects data for setting a region basedon the intersection position and the travel trajectory of the vehicle 9as the monitoring region when performing driving assistance. At thistime, the processing unit 101 selects data obtained by deleting a partof the data acquired in S10 based on the intersection position. Notethat details of this step will be described later.

In S16, the processing unit 101 stores the data selected in S15.Furthermore, the processing unit 101 stores the data obtained bypartially deleting, in S15, the data temporarily stored in the storageunit 102 in the monitoring region DB 1022 of the storage unit 102 as themonitoring region information. Thereafter, the processing unit 101 endsthe flowchart.

In S17, the processing unit 101 deletes the data temporarily stored inthe storage unit 102. That is, in a case where the intersection positioncannot be specified in S12, the processing unit 101 deletes the entiredata acquired in S10. Since data not used for setting the monitoringregion is deleted as described above, the amount of data stored in thestorage unit 102 can be reduced. Thereafter, the processing unit 101ends the flowchart.

As described above, since the data obtained by deleting a part of thedata acquired in S10 based on the intersection position is selected inS15, the amount of data used for setting the monitoring region indriving assistance can be reduced.

3.2. Example of Data Selection Processing

FIG. 8 is a flowchart illustrating a processing example of theprocessing unit 101, and illustrates a specific processing example ofS15 of FIG. 5.

In S1501, the processing unit 101 acquires an angular difference inorientation from the previous position. More specifically, theprocessing unit 101 uses the data acquired in S10 to acquire an angulardifference between an orientation at each of the positions 971 to 976and an orientation at an immediately previous position in time serieswith an intersection position 51 as the start point. Here, FIG. 7B is adiagram illustrating an angular difference between each position ofanother vehicle and a previous position. For example, since theorientation of the vehicle 9 at the intersection position 51 and theposition 976 is 90°, an angular difference in orientation between theposition 977 and the previous position is 0°. Further, for example,since the orientation of the vehicle 9 at the position 975 is 80°, anangular difference in orientation between the position 976 and theprevious position is 10°. In this manner, the processing unit 101acquires the angular difference in orientation between each of thepositions 971 to 976 and the intersection position 51 and the previousposition.

Here, the processing unit 101 may estimate the orientation at theintersection position 51 based on the position 976 and the position 977.For example, the processing unit 101 may set, as the orientation at theintersection position 51, an orientation of a vector with the position976 as the start point and the position 977 as the end point.Furthermore, the processing unit 101 may estimate the orientation at theintersection position 51 based on a value of an orientation 966 or 967.For example, the processing unit 101 may adopt, as the orientation atthe intersection position 51, the orientation 966 at the position 976,which is a data point immediately before the intersection position 51,or the orientation 967 at the position 977, which is a data pointimmediately after the intersection position 51.

In S1502, the processing unit 101 acquires a cumulative value of anabsolute value of the angular difference. More specifically, theprocessing unit 101 calculates and acquires the cumulative value of theabsolute value of the angular difference from the immediately previousposition in time series with the intersection position 51 as the startpoint (FIG. 7B).

In S1503, the processing unit 101 checks whether or not the cumulativevalue acquired in S1502 exceeds a threshold. In a case where thecumulative value exceeds the threshold, the processing unit 101 proceedsto S1504. In a case where the cumulative value does not exceed thethreshold, the processing unit 101 proceeds to S1506. For example, thethreshold here may be set in a range of 60° to 210°. Furthermore, thethreshold may be set in a range of 90° to 180° or 120° to 150°, or maybe set to 135°.

In S1504, the processing unit 101 deletes data for a position previousto a position at which the cumulative value exceeds the threshold. Forexample, in a case where the threshold is set to 135°, the cumulativevalue of the absolute value of the angular difference at the position972 exceeds the threshold. Therefore, the processing unit 101 deletesdata (Data Nos. 9000 and 9001 in FIG. 7A) for positions previous to theposition 972 from the data acquired from the vehicle 9 and temporarilystored in the storage unit 102.

In S1505, the processing unit 101 selects the remaining data.Furthermore, the processing unit 101 selects data for setting, as themonitoring region when performing driving assistance, the data (DataNos. 9002 to 9007 in FIG. 7A) not deleted in S1504 from the dataacquired from the vehicle 9 and temporarily stored in the storage unit102. Thereafter, the processing unit 101 ends this flowchart andproceeds to S16 of FIG. 5. Accordingly, the data of Data Nos. 9002 to9007 in FIG. 7A are registered in the monitoring region DB 1022.Therefore, in this case, a monitoring region 991 of FIG. 6 is set.

On the other hand, when the processing unit 101 proceeds to S1506, theprocessing unit 101 deletes the entire data acquired from the vehicle 9and temporarily stored in the storage unit 102. Thereafter, theprocessing unit 101 ends this flowchart and proceeds to S16 of FIG. 5,but since there is no selected data, the processing unit 101 ends theflowchart of FIG. 5 without storing data in the monitoring region DB1022.

In this manner, the processing unit 101 deletes a part of the dataacquired from the vehicle 9 based on a change in orientation at each ofthe positions 970 to 977 of the vehicle 9. Since data to be used forsetting the monitoring region is selected according to the change inorientation of another vehicle, the amount of data can be reduced whilesetting the monitoring region more appropriately.

In addition, in the present embodiment, data regarding a positionprevious to a position at which the cumulative value of the absolutevalue of the angular difference exceeds the threshold, starting from theintersection position 51, is deleted. Since the data regarding theposition previous to the position at which the cumulative value exceedsthe threshold is deleted, the amount of data can be reduced whilesetting the monitoring region more appropriately.

Further, in the present embodiment, since the control device 10 performsdriving assistance based on the data acquired in vehicle-to-vehiclecommunication, it is possible to perform driving assistance of theself-vehicle without using the map information. Then, in a case wherethe driving assistance of the self-vehicle is performed without usingthe map information, the amount of data for performing the drivingassistance can be reduced.

Note that, in the present embodiment, the processing unit 101 deletesthe data regarding the position previous to the position at which thecumulative value of the absolute value of the angular difference exceedsthe threshold, but may delete the data regarding the position previousto the position at which the cumulative value of the absolute value ofthe angular difference exceeds the threshold and the position at whichthe cumulative value of the absolute value of the angular differenceexceeds the threshold.

4. MODIFICATION EXAMPLES 4.1. Modification Examples of Data SelectionProcessing 4.1.1. Modification Example 1 (FIG. 9)

FIG. 9 is a flowchart illustrating a processing example of theprocessing unit 101, and illustrates a specific processing example ofS15 of FIG. 5.

In S1511, the processing unit 101 acquires a passage time (hereinafter,the passage time may be referred to as a passage time T) of the vehicle9, which is another vehicle, at the intersection position 51. Forexample, the processing unit 101 calculates the passage time T based onthe positions including the position 977, the position 976, and theintersection position 51 and the passage times of the vehicle 9 at theposition 977 and the position 976.

In S1512, the processing unit 101 checks whether or not there is dataoutside a predetermined period based on the passage time of the vehicle9 at the intersection position 51 acquired in S1511. In a case wherethere is data outside the predetermined period, the processing unit 101proceeds to S1513, and in a case where there is no data outside thepredetermined period, the processing unit 101 proceeds to S1515. Forexample, the predetermined period may be a period from a time point apredetermined time before the passage time T to the passage time T. Thepredetermined time may be, for example, several seconds to several 10seconds.

In S1513, the processing unit 101 deletes the data outside thepredetermined period. Furthermore, the processing unit 101 deletes, fromthe data acquired in S10, data for a time point outside thepredetermined period based on the passage time T, which is the time atwhich the vehicle 9, which is the other vehicle, is positioned at theintersection position 51. A specific description will be given withreference to FIG. 7A. It is assumed that the predetermined period inS1512 is a period from a time point 30 seconds before the passage time Tto the passage time T. In addition, it is assumed that the time t3 is 27seconds before the passage time T and the time t2 is 32 seconds beforethe passage time T. In such a case, data of Data No. 9003 is data for atime point within the predetermined period, and data of and before DataNo. 9002 is data for a time point outside the predetermined period.Therefore, the processing unit 101 deletes the data (Data Nos. 9000 to9002) of and before Data No. 9002.

In S1514, the processing unit 101 selects the remaining data. That is,the processing unit 101 selects data that has not been deleted in S1513from the data acquired in S10. For example, in a case where the data(Data Nos. 9000 and 9001) before Data No. 9002 is deleted in S1513, theprocessing unit 101 selects data (Data Nos. 9002 to 9007) of or afterData No. 9002.

In S1515, the processing unit 101 selects the entire data. That is, in acase where the entire data acquired in S10 has been acquired at a timepoint within the predetermined period, the processing unit 101 selectsthe entire data acquired in S10.

As described above, according to this modification example, since datafor a time point outside the predetermined period is deleted, it ispossible to reduce the amount of data while setting the monitoringregion more appropriately.

4.1.2. Modification Example 2 (FIG. 10)

FIG. 10 is a flowchart illustrating a processing example of theprocessing unit 101, and illustrates a specific processing example ofS15 of FIG. 5.

In S1521, the processing unit 101 checks whether or not the dataacquired from the vehicle 9, which is the other vehicle, in S10 includesa lighting history of the turn signal. In a case where the data includesthe lighting history, the processing unit 101 proceeds to S1522. In acase where the data does not include the lighting history, theprocessing unit 101 proceeds to S1524. In the example of FIG. 7A, sincethere is a history showing that the left turn signal of the vehicle 9 islighted at the position 971, the processing unit 101 proceeds to S1522.

In S1522, the processing unit 101 deletes data before the turn signal islighted from the data acquired in S10. In the example of FIG. 7A, sinceData No. 9001 includes data indicating that the turn signal is lighted,the processing unit 101 deletes data of Data No. 9000 that is databefore the turn signal is lighted. In the present embodiment, databefore the turn signal is lighted is deleted, but data when the turnsignal is lighted may also be deleted. That is, the data of Data No.9001 in the example of FIG. 7A may also be deleted.

In S1523, the processing unit 101 selects the remaining data. That is,the processing unit 101 selects data that has not been deleted in S1522from the data acquired in S10. For example, in a case where the data ofData No. 9000 is deleted in S1522, the processing unit 101 selects data(Data Nos. 9001 to 9007) of and after Data No. 9001.

In S1524, the processing unit 101 selects the entire data. That is, in acase where the data acquired in S10 does not include the data indicatingthat the turn signal is lighted, the processing unit 101 selects theentire data acquired in S10.

According to this embodiment, since the data before the turn signal islighted is deleted, it is possible to reduce the amount of data whilesetting the monitoring region more appropriately.

4.2. Modification Example of Intersection Position RegistrationProcessing 4.2.1. Modification Example 1 (FIG. 11)

FIG. 11 is a flowchart illustrating a processing example of theprocessing unit 101, and illustrates a processing example of theintersection position registration processing. Hereinafter, the sameprocessing as that in the flowchart of FIG. 5 is denoted by the samereference sign, and a description thereof is omitted.

At the branch of S13, in a case where the intersection position can bespecified in S12, the processing unit 101 proceeds to S21.

In S21, the processing unit 101 performs preferential roaddetermination. More specifically, in a case where the intersectionposition can be specified in S12, the processing unit 101 determineswhether or not a road on which the vehicle 1, which is the self-vehicle,has been traveling is a preferential road. The processing unit 101 maydetermine whether or not the road on which the vehicle 1 has beentraveling is the preferential road based on a travel history of thevehicle 1 which is the self-vehicle. For example, when the vehicle 1stops before the intersection position, the processing unit 101determines that the road on which the vehicle 1 has been traveling isnot the preferential road. As a result, the processing unit 101 candetermine the preferential road according to the travel history of theself-vehicle. In addition, the processing unit 101 may determine whetheror not the road on which the vehicle 1 has been traveling is thepreferential road based on a surrounding situation of the intersectionposition. For example, the processing unit 101 may determine whether ornot the road on which the vehicle 1 has been traveling is thepreferential road by recognizing a stop line or a sign, comparing avehicle width between a traveling road and a crossroad, and the likebased on the detection result of the outside detection sensor includedin the sensor group 11.

In S22, based on the determination result in S21, the processing unit101 proceeds to S14 in a case where the vehicle 1, which is theself-vehicle, is not traveling on the preferential road, and theprocessing unit 101 proceeds to S17 in a case where the vehicle 1 istraveling on the preferential road. As a result, in a case where it isdetermined in S21 that the road on which the vehicle 1, which is theself-vehicle, has been traveling is not the preferential road, theprocessing unit 101 deletes, in S15, a part of the data acquired fromthe vehicle 9 in S10. On the other hand, in a case where it isdetermined in S21 that the road on which the vehicle 1, which is theself-vehicle, has been traveling is the preferential road, theprocessing unit 101 deletes, in S17, the entire data acquired from thevehicle 9 in S10.

According to this modification example, since the monitoring region isnot set in a case where the self-vehicle is traveling on thepreferential road, it is possible to suppress the driving assistancefrom being performed in a situation where the necessity of the drivingassistance is low. In addition, since the monitoring region is not setin a region where the necessity of the driving assistance is low, theamount of data stored in the storage unit 102 can be reduced.

4.2.2. Modification Example 2 (FIG. 12)

FIG. 12 is a flowchart illustrating a processing example of theprocessing unit 101, and illustrates a processing example of theintersection position registration processing. Hereinafter, the sameprocessing as that in the flowchart of FIG. 5 is denoted by the samereference sign, and a description thereof is omitted.

At the branch of S13, in a case where the intersection position can bespecified in S12, the processing unit 101 proceeds to S21.

In S31, the processing unit 101 determines whether or not there is atraffic light. More specifically, in a case where the intersectionposition can be specified in S12, the processing unit 101 determineswhether or not the traffic light is provided at the specifiedintersection position. The processing unit 101 may determine whether ornot there is a traffic light at the intersection position based on thedetection result of the outside detection sensor included in the sensorgroup 11.

In S32, in a case where it is determined in S31 that there is no trafficlight at the intersection position, the processing unit 101 proceeds toS14, and in a case where it is determined in S31 that there is a trafficlight at the intersection position, the processing unit 101 proceeds toS17. Therefore, in a case where it is determined in S31 that the trafficlight is not provided at the intersection position, in S15, theprocessing unit 101 deletes a part of the data acquired from the vehicle9 in S10. On the other hand, in a case where it is determined in S31that the traffic light is provided at the intersection position, theprocessing unit 101 deletes the entire data acquired from the vehicle 9in S10.

According to this embodiment, since the monitoring region is not set ina case where the traffic light is provided at the intersection position,it is possible to suppress the driving assistance from being performedin a situation where the necessity of the driving assistance is low. Inaddition, since the monitoring region is not set in a region where thenecessity of the driving assistance is low, the amount of data stored inthe storage unit 102 can be reduced.

5. Other Embodiments

In the above-described embodiment, the control device 10 functioning asthe driving assistance device is mounted on the four-wheeled vehicle 1,but the control device 10 may be mounted on another type of vehiclecapable of traveling on a road, such as a straddled vehicle or a workmachine.

6. Summary of Embodiments

The embodiments described above disclose at least the following drivingassistance device, vehicle, and driving assistance method.

1. A driving assistance device (10) in the above embodiments comprising:

an acquisition unit (101, S10) configured to acquire data regarding atravel trajectory of another vehicle from the other vehicle byvehicle-to-vehicle communication;

a specifying unit (101, S12) configured to specify an intersectionposition between the travel trajectory of the other vehicle and a traveltrajectory of a self-vehicle based on the data acquired by theacquisition unit; and a selection unit (101, S15) configured to selectdata for setting a region based on the intersection position and thetravel trajectory of the other vehicle as a monitoring region whenperforming driving assistance in a case where the intersection positionis specifiable by the specifying unit, wherein the selection unitselects data that has been partially deleted from the data acquired bythe acquisition unit based on the intersection position.

According to this embodiment, since the data obtained by deleting a partof the data acquired by the acquisition unit based on the intersectionposition is selected, it is possible to reduce the amount of data usedfor setting the monitoring region for another vehicle in drivingassistance.

2. According to the above embodiments, the driving assistance devicefurther comprises a deletion unit (101, S16) configured to delete theentire data acquired by the acquisition unit in a case where theintersection position is not specifiable by the specifying unit.

According to this embodiment, since data not used for setting themonitoring region is deleted, it is possible to reduce the amount ofdata stored in the device.

3. According to the above embodiments, the data acquired by theacquisition unit includes data indicating a position and an orientationof the other vehicle in time series, and the selection unit deletes apart of the data acquired by the acquisition unit based on a change ofthe orientation (S1504).

According to this embodiment, since data to be used for setting themonitoring region is selected according to the change in orientation ofanother vehicle, it is possible to reduce the amount of data whilesetting the monitoring region more appropriately.

4. According to the above embodiments, the selection unit acquires anangular difference in orientation between each position of the othervehicle and an immediately previous position in time series, and deletesdata regarding a position previous to a position at which a cumulativevalue of an absolute value of the angular difference exceeds athreshold, starting from the intersection position (S1504).

According to this embodiment, since the data regarding the positionprevious to the position at which the cumulative value exceeds thethreshold is deleted, it is possible to reduce the amount of data whilesetting the monitoring region more appropriately.

5. According to the above embodiments, the selection unit deletes, fromthe data acquired by the acquisition unit, data for a time point outsidea predetermined period based on a time point at which the other vehicleis positioned at the intersection position (S1513).

According to this embodiment, since the data for the time point outsidethe predetermined period is deleted, it is possible to reduce the amountof data while setting the monitoring region more appropriately.

6. According to the above embodiments, the data acquired by theacquisition unit includes data regarding whether or not a turn signal ofthe other vehicle is lighted, and the selection unit deletes data beforethe turn signal is lighted from the data acquired by the acquisitionunit (S1522).

According to this embodiment, since the data before the turn signal islighted is deleted, it is possible to reduce the amount of data whilesetting the monitoring region more appropriately.

7. According to the above embodiments, the driving assistance devicefurther comprising an assistance unit (101, S94) configured to performthe driving assistance in a case where another vehicle is present in themonitoring region.

According to this embodiment, it is possible to perform the drivingassistance based on the set monitoring region.

8. According to the above embodiments, the assistance unit makes anotification for an occupant of the self-vehicle as the drivingassistance (S94).

According to this embodiment, it is possible to urge the occupant tograsp the surrounding situation of the self-vehicle.

9. According to the above embodiments, the driving assistance devicefurther comprises a first determination unit (101, S21) configured todetermine whether or not a road on which the self-vehicle has beentraveling is a preferential road in a case where the intersectionposition is specifiable by the specifying unit,

wherein in a case where the first determination unit determines that theroad on which the self-vehicle has been traveling is not thepreferential road, the selection unit deletes a part of the dataacquired by the acquisition unit (S15), and

in a case where the first determination unit determines that the road onwhich the self-vehicle has been traveling is the preferential road, thedeletion unit deletes the entire data acquired by the acquisition unit(S17).

According to this embodiment, since the monitoring region is not set ina case where the self-vehicle is traveling on the preferential road, itis possible to suppress the driving assistance from being performed in asituation where the necessity of the driving assistance is low.

10. According to the above embodiments, the first determination unitdetermines that the road on which the self-vehicle has been traveling isnot the preferential road in a case where the self-vehicle stops beforethe intersection position (S21).

According to this embodiment, it is possible to determine thepreferential road according to the travel history of the self-vehicle.

11. According to the above embodiments, the driving assistance devicefurther comprises a second determination unit (S101, S31) configured todetermine whether or not a traffic light is provided at the intersectionposition,

wherein in a case where the second determination unit determines that atraffic light is not provided at the intersection position, theselection unit deletes a part of the data acquired by the acquisitionunit (S15), and

in a case where the second determination unit determines that a trafficlight is provided at the intersection position, the deletion unitdeletes the entire data acquired by the acquisition unit (S17).

According to this embodiment, since the monitoring region is not set ina case where the traffic light is provided, it is possible to suppressthe driving assistance from being performed in a situation where thenecessity of the driving assistance is low.

12. According to the above embodiments, the driving assistance devicefurther comprises a storage unit (102) configured to store the dataselected by the selection unit.

According to this embodiment, it is possible to store data selected bythe selection unit.

13. According to the above embodiments, the driving assistance of theself-vehicle is performed without using map information.

According to this embodiment, it is possible to perform the drivingassistance based on travel data of the self-vehicle and travel dataacquired from another vehicle by vehicle-to-vehicle communicationwithout using map information.

14. A vehicle (1) in the above embodiments mounts the driving assistancedevice in the above embodiments.

According to this embodiment, there is provided a vehicle on which thedriving assistance device capable of reducing the amount of data usedfor setting the monitoring region for another vehicle in the drivingassistance is mounted.

15. A driving assistance method in the above embodiments comprising:

acquiring (S10) data regarding a travel trajectory of another vehiclefrom the other vehicle by vehicle-to-vehicle communication;

specifying (S12) an intersection position between the travel trajectoryof the other vehicle and a travel trajectory of a self-vehicle based onthe data acquired in the acquiring; and

selecting (S15) setting data for setting a region based on theintersection position and the travel trajectory of the other vehicle asa monitoring region when performing driving assistance in a case wherethe intersection position is specifiable in the specifying,

wherein, in the selecting, data that has been partially deleted from thedata acquired in the acquiring based on the intersection position isselected.

According to this embodiment, since the data obtained by deleting a partof the data acquired by the acquisition unit based on the intersectionposition is selected, it is possible to reduce the amount of data usedfor setting the monitoring region for another vehicle in drivingassistance.

The invention is not limited to the foregoing embodiments, and variousvariations/changes are possible within the spirit of the invention.

What is claimed is:
 1. A driving assistance device comprising: anacquisition unit configured to acquire data regarding a traveltrajectory of another vehicle from the other vehicle byvehicle-to-vehicle communication; a specifying unit configured tospecify an intersection position between the travel trajectory of theother vehicle and a travel trajectory of a self-vehicle based on thedata acquired by the acquisition unit; and a selection unit configuredto select data for setting a region based on the intersection positionand the travel trajectory of the other vehicle as a monitoring regionwhen performing driving assistance in a case where the intersectionposition is specifiable by the specifying unit, wherein the selectionunit selects data that has been partially deleted from the data acquiredby the acquisition unit based on the intersection position.
 2. Thedriving assistance device according to claim 1, further comprising adeletion unit configured to delete the entire data acquired by theacquisition unit in a case where the intersection position is notspecifiable by the specifying unit.
 3. The driving assistance deviceaccording to claim 1, wherein the data acquired by the acquisition unitincludes data indicating a position and an orientation of the othervehicle in time series, and the selection unit deletes a part of thedata acquired by the acquisition unit based on a change of theorientation.
 4. The driving assistance device according to claim 3,wherein the selection unit acquires an angular difference in orientationbetween each position of the other vehicle and an immediately previousposition in time series, and deletes data regarding a position previousto a position at which a cumulative value of an absolute value of theangular difference exceeds a threshold, starting from the intersectionposition.
 5. The driving assistance device according to claim 1, whereinthe selection unit deletes, from the data acquired by the acquisitionunit, data for a time point outside a predetermined period based on atime point at which the other vehicle is positioned at the intersectionposition.
 6. The driving assistance device according to claim 1, whereinthe data acquired by the acquisition unit includes data regardingwhether or not a turn signal of the other vehicle is lighted, and theselection unit deletes data before the turn signal is lighted from thedata acquired by the acquisition unit.
 7. The driving assistance deviceaccording to claim 1, further comprising an assistance unit configuredto perform the driving assistance in a case where another vehicle ispresent in the monitoring region.
 8. The driving assistance deviceaccording to claim 7, wherein the assistance unit makes a notificationfor an occupant of the self-vehicle as the driving assistance.
 9. Thedriving assistance device according to claim 2, further comprising afirst determination unit configured to determine whether or not a roadon which the self-vehicle has been traveling is a preferential road in acase where the intersection position is specifiable by the specifyingunit, wherein in a case where the first determination unit determinesthat the road on which the self-vehicle has been traveling is not thepreferential road, the selection unit deletes a part of the dataacquired by the acquisition unit, and in a case where the firstdetermination unit determines that the road on which the self-vehiclehas been traveling is the preferential road, the deletion unit deletesthe entire data acquired by the acquisition unit.
 10. The drivingassistance device according to claim 9, wherein the first determinationunit determines that the road on which the self-vehicle has beentraveling is not the preferential road in a case where the self-vehiclestops before the intersection position.
 11. The driving assistancedevice according to claim 2, further comprising a second determinationunit configured to determine whether or not a traffic light is providedat the intersection position, wherein in a case where the seconddetermination unit determines that a traffic light is not provided atthe intersection position, the selection unit deletes a part of the dataacquired by the acquisition unit, and in a case where the seconddetermination unit determines that a traffic light is provided at theintersection position, the deletion unit deletes the entire dataacquired by the acquisition unit.
 12. The driving assistance deviceaccording to claim 1, further comprising a storage unit configured tostore the data selected by the selection unit.
 13. The drivingassistance device according to claim 1, wherein the driving assistanceof the self-vehicle is performed without using map information.
 14. Avehicle on which the driving assistance device according to claim 1 ismounted.
 15. A driving assistance method comprising: acquiring dataregarding a travel trajectory of another vehicle from the other vehicleby vehicle-to-vehicle communication; specifying an intersection positionbetween the travel trajectory of the other vehicle and a traveltrajectory of a self-vehicle based on the data acquired in theacquiring; and selecting setting data for setting a region based on theintersection position and the travel trajectory of the other vehicle asa monitoring region when performing driving assistance in a case wherethe intersection position is specifiable in the specifying, wherein, inthe selecting, data that has been partially deleted from the dataacquired in the acquiring based on the intersection position isselected.